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Патент USA US3077114

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United States Patent O?lice
3,077,104
Patented Feb. 12, 1963
it
2
serves as a quantitative marker for the interface or mix
3,677,1ii4
PRGCESS FUR DETECTING THE ENTERFACE
BETWEEN TWO ABJAQENT FLUED§
Frank C. Fowler, 1451B). 76th Terrace,
Kansas City 10, M0.
N0 Drawing. Fiied May 27, 1959, Ser. No. 816,653
3 (Claims. (Ci. ‘73-53)
ture separating two adjacent ?uids.
In another aspect of this invention, the halogenated
hydrocarbon is admixed with the fluid to be transported
through the conduit. If any leaks are present in the con
duit for transporting the ?uid, portable detecting equip
ment is passed along the conduit to detect the presence of
the halogenated hydrocarbon. Very minute quantities of
The present invention relates to a novel and useful
the halogenated hydrocarbon can be detected thereby in
method of detection of the presence of materials and to a 10 dicating the presence of a leak in the conduit.
composition used therefor. In one aspect my invention
The halogenated hydrocarbon used as the detecting
relates to a method for detecting the interface between
medium may be partially or completely halogenated; and
two adjacent ?uids when ?owing successively through a
preferably, the halogens are selected from the group con
conduit. In another aspect this invention relates to a
sisting of ?uorine and chlorine. The halogenated hydro
method for detecting leaks of ?uids from con?ned areas. 15 carbon should be miscible with the ?uids to be trans
There has been an increasing demand for a method of
ported when in the liquid phase. That is, the halogenated
accurately detecting and measuring the interface separat
ing adjacent products in a product pipeline. The several
methods in use can be classi?ed into two groups.
One
hydrocarbon should be soluble in the liquid ?uid to be
transported in the amounts necessary for proper detection.
Preferably, the halogenated hydrocarbon is normally gase
group involves those measuring a property of the product 20 ous material. Suitable examples of halogenated hydro
being transported, such as density, ?ash point or dielectric
carbon are those containing ?uorine or chlorine or both,
constant. The other group measures a property of a
having not more than three carbon atoms per molecule.
tracer or marker which is injected into the line at the inter
However, halogenated hydrocarbon of longer chain length
face. The marker may be a dye or a radioactive tracer.
may be used Without departing from the scope of this in
The di?iculty with measuring a property of the prod 25 vention. Typical examples of the halogenated hydro
ucts is that occasionally products with nearly identical
carbon include dichlorodi?uoromethane, dichloromono
properties are adjacent to each other in the pipeline. For
?uoromethane, trichloromono?uoromethane, trichlorotri
instance, it is possible for two gasolines to have almost
?uoroethane, and dichlorotetra?uoroethane. Since for the
identical densities or dielectric constants. This situation
best detection process it is desirable that the halogenated
produces such little change in the measured quantity that
hydrocarbon be in the vapor phase, the above compounds
an interface cannot be detected. Rarely will large ship,
are particularly useful since they are normally gaseous.
ments of products be characterized by exactly the same
However, any halogenated hydrocarbon which is volatiliz
density or dielectric constant because uniform mixing
able is usable, such as chloroform, carbon tetrachloride,
throughout large storage tanks does not exist. Thus, mis
and tetrachloroethylene, which are normally liquid but
leading indications of the presence of an interface can 35 volatilizable. Mixtures of the halogenated hydrocarbon
occur because of inability to insure complete homogeneity ‘ may be used without departing from the scope of this in
within the storage tanks and transfer lines.
vention. Such mixtures are particularly desirable to pro
The use of a dye as a marker which depends upon visual
vide a vapor pressure of the detecting medium correspond
or colorimetric measurements has certain disadvantages.
ing substantially to‘ the vapor pressure of the fluid to be
Certain products, particularly crude oil, possess color 40 transported. ' A particularly desirable mixture is a mix
which interferes with visual observations. Measurement
of color with colorimetric equipment requires expensive
apparatus, costly to install and maintain under ?eld con
ditions. Radioactive tracers present the problem of ade
quate safety measures to insure the safety of operators.
An object of this invention is to provide a method for detecting the presence of ?uids.
Another object of this invention is to provide a method
for detecting different ?uids while ?owing in a conduit. 50
Still another object of this invention is to‘provide a
method for detecting leaks of ?uids from con?ned areas.
Still another object of this invention is to provide de
tecting medium which is miscible and inert with the ?uids
to be detected.
Still another object of this invention is to provide a
detecting medium which is more sensitive and more eco
nomical than present media used for detecting the pres
ence of ?uids.
ture of dichlorodi?uoromethane and dichlorotetra?uoro
ethane in equal molar proportions when used as a detecf
tion medium for transporting hydrocarbon.
The detection medium should be present in an amount
at least 0.1 p.p.n1., and preferably, an amount between
about 25 and about 500 ppm. In these proportions the
halogenated hydrocarbon is usually miscible with most
organic ?uids. In most instances, it is unnecessary to use
much more than 100-150 ppm. of the halogenated hy
drocarbon for detection purposes. In the case of detect
ing leaks in conduits in which the ?uid is being held, as
small as 1-10 ppm. of the halogenated hydrocarbon is
all that is required.
'
The present invention is particularly useful in trans
porting hydrocarbons, particualriy in the transportation
of petroleum oils and distillates. ‘For example, the pres
ent invention applies to transporting crude oil, gasolines,
kerosenes, diesel oil,‘ fuel oil and various petroleum dis
Various other objects and advantages will become ap 60 tillates. The invention also is applicable to the trans
portation of other organic chemicals, such as alcohol,
parent to those skilled in the art from the accompanying
description and disclosure.
According to the present invention, a halogenated hy
drocarbon is injected into the final portion of the leading
ethylene, propane and ethylene glycol.
The invention applies particularly to the transporta
tion of various petroleum liquids and fractions. For
the interface is detected. The halogenated hydrocarbon
present invention, therefore, is an economical and sensi
example, in the transportation of crude oil it is necessary
?uid or the initial portion of the flowing ?uid in a conduit 65 often to detect the difference between crude oil supplied
in which the ?uids are ?owing successively through said
by different suppliers or to indicate the crude oil to differ
conduit. Equipment capable of detecting the halogenated
ent customers. In addition, different products in quality
hydrocarbon is located downstream from the point of in
and grade may be transported through the same conduit,
jection. As the interface containing the halogenated hy
70 but their physical and chemical properties are so closely
drocarbon passes the detecting equipment, the presence of
similar that it is di?icult to detect the interface. The
3,077,104
3
4
tive method for detecting the interface between similar
petroleum products, such as two different gasolines or
gasoline and kerosene, etc. In this respect, in transport
The detecting equipment would function by diverting
had been marked, then the Freon concentrations would
gradually rise to the concentration at which it was in
jected. In this example, the value would be 100 p.p.m.
As the interface passed the measuring station, the Freon
concentration would decrease again, reaching zero when
all of the mixture had passed. Similar results are also
obtained by injection of the Freon into the ?rst portion
of gasoline B. Still another method involves injection of
a small stream as a vapor from the conduit or pipeline
a concentrated quantity of Freon at the interface for a
ing gasolines the halogenated hydrocarbon mentioned
above is inert‘ and has no effect upon the anti-knock prop
erties of the gasoline when used in the proportions set
forth above.
to the measuring element. One typical method of detect 10 shorter time. Detection elements located downstream
would give a zero reading followed by a rapidly increas
ing halogenated hydrocarbons, such as the ?uorine-con
ing reading to a maximum value. The value would then
taining Freons, is based upon the principle that a heated
decrease rapidly to Zero again.
platinum surface emits substantially larger numbers of
A Freon ?ag would not be affected by contamination
ions in the presence of halogen gases. Suitable equip
ment of this nature is available on the open market and 15 from line-?lls, line-traps or leaking valves. This factor
gives erroneous results when using the physical property
one such equipment is sold by the General Electric Com
of the products as a means of identi?cation.
pany as G.E.-C233G leak detector used for detecting
Besides identifying the interface, the use of Freon ?ags
Freons. Another useful method is to take advantage of
offers a very sensitive method of detecting small leaks
the green color imparted to the burning ?ame of hydro
carbons by the presence of halogen. Thus, a small sam~ 20 from the pipeline. Concentrations of less than 1 p.p.m.
Freon in air may be easily detected. The use of the more
ple of a ?owing hydrocarbon in the conduit may be
volatile Freons increases the concentration of Freon in
burned to indicate the presence of halogens.
air resulting from a pipeline leak.
Several methods may be used for converting the liquid
As a speci?c example of the operation of this invention
stream in the conduit to vapor to be passed through the
detecting equipment. Among these are:
25 in the transportation of two different batches of gasolines
through a 100 mile long 8 inch pipeline at the source
of supply, 100 p.p.m. of Freon~12 is injected into 300
barrels of the ?rst batch of gasoline at the end of the
supply of such gasoline and before the supply of the
(4) Combustion of liquid with measurement on the ?ue
30 second batch of gasoline. This corresponds to about one
gases
mile of injection in the pipeline. At the end of the
Any of the above methods may be used to produce the
100 mile pipeline more than 300 barrels of gasoline will
desired results. Sensitivity, safety and economy dictate
be marked by the Freon due to diffusion. The detection
their choice.
equipment will ?rst indicate 0 p.p.m. of the Freon and
The Freons as the detecting media offer a wide range
gradually indicate higher quantities until it reaches about
35
of boiling points which, in turn, permit a wide choice of
100 p.p.m. This will allow sufficient time for the oper
methods for injection and detection. Choice of different
ator to be ready to mark the change in the interface.
Freons allows variation of the sensitivity required in de
Then, when the detection equipment starts to indicate a
tection. The most urgent need for better methods of
decreasing Freon concentration, the operator will know
detection is in product pipelines, where the principal prod
that the interface has arrived.
ucts to be transported are gasoline and light distillates.
Various modi?cations and alterations of the quantity
The use of Freons as a detecting media is adaptable to a
and means of detection may become obvious to those
wide variation of petroleum products from methane
skilled in the art without departing from the scope of
through crude oil. As a matter of fact, of the current
this invention.
methods in use, none seems well suited to the identi?ca
Having described my invention, I claim:
tion of crude oil interfaces. Freons can be used quite 45
1. A method for detecting the interface between two
satisfactorily in crude oil lines. Increasing use of pipe
adjacent
batches of gasoline successively ?owing through
lines for shipment of chemicals is being made. The
a conduit which comprises injecting a miscible ?uorinated
Freons will perform well in most applications of chemi
hydrocarbon adjacent to said interface in an amount
cal shipments.
Freons or halogenated hydrocarbons offer some impor 50 between about 0.1 and about 500 p.p.m. of the gasoline
and subsequently downstream from the point of injection
tant advantages when used as markers. First of all, they
removing a portion of the gasoline containing said ?uori
'are completely miscible with hydrocarbons and many
nated hydrocarbon, vaporizing said portion of the gasoline
other chemicals in the ranges under consideration. Spe
thus removed and determining the presence of ?uorinated
ci?cally in the transportation of petroleum products by
pipelines, small quantities used in this invention do not 55 hydrocarbon in said gasoline.
2. The process of claim 1 in which said ?uorinated
affect the speci?cations or the use of the products. Many
hydrocarbon is a mixture of dichlorodi?uoromethane and
of the Freons possess the added advantage of being non
dichlorotetra?uoroethane.
toxic and non?amma-ble.
3. A method for detecting the interface between two
A Freon or a mixture of Freons selected for a‘ given
identi?cation would be injected at a speci?c rate, depend 60 adjacent batches of hydrocarbons successively ?owing
through a conduit which comprises injecting a miscible
ing upon the concentrations desired in one of the two
?uorinated hydrocarbon adjacent to said interface in
adjacent products. For instance, Freon-12 could be in
an amount between about 0.1 and about 500 p.p.m. of
jected into the gasoline at the rate such that the concen
the hydrocarbon and subsequently downstream from the
tration would be 100 p.p.m. Freon-12 in the gasoline.
This would be done in one of the two adjacent gasolines 65 point of injection removing a portion of the hydrocarbon
(1) vaporization by application of heat
(2) Flashing by reduction in pressure
(3) Stripping by inert gas such as nitrogen
being pumped through pipelines. If gasoline A were
being pumped into a pipeline followed by gasoline B, then
the interface between the two gasolines would be a mix
ture of A and B. Consider that the Freon were injected
in the last portion of the gasoline A as it was being pumped 70
into the pipeline. The measuring instrument, located at
the next station, would indicate zero p.p.m. Freon at ?rst.
Then the measuring element would detect increasing
amounts of Freon in gasoline A as the interface ap
proached that station. It su?icient quantity of gasoline 75
containing said ?uorinated hydrocarbon, vaporizing said
portion of the hydrocarbon thus removed and determin
ing the presence of ?uorinated hydrocarbon in said hydro
carbon.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,090,737
McDonald __________ __ Mar. 17, 1914
(Other references on following page)
5
3,077,104
UNITED STATES PATENTS
1,693,737
Weldon _____________ __ Dec. 4, 1928
2,631,242
2,631,929
Metcaif ____________ __ Mar. 10, 1953
2,775,120
Thorpe et a1. _______ __ Mar. 17, 1953
Bennett ct a1. ________ _.. Dec. 25, 1956
6
2,784,160
2,868,625
Blaker ______________ __ Mar. 5, 1957
Frank ______________ __ Jan. 13, 1959
OTHER REFERENCES
General Electric Review. October 1949, pages 41-44,
article by J. R. Ne?.
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